Otic vesicle size is affected by the overexpression of fgf8 depending on the developmental stage. (A, B) Overexpression of fgf8 by mRNA injections at the 1-cell stage completely ablates all indications of otic fate (27/40 embryos, B) in comparison to wild-type vesicles (A). (C-E) Misexpression of fgf8 at 30% epiboly (28/28 embryos, C), shield stage (27/28 embryos, D) and 75% epiboly (29/29 embryos, E) results in smaller otic vesicles. (F-H) Otic vesicles are increased in size if fgf8 is misexpressed at the tailbud (26/29 embryos, F) or the 4-somite stage (24/28 embryos, G) whereas at the 8-somite stage no change in vesicle size is observed (26/26 embryos, H). Lateral views of otic vesicles highlighted with starmaker at 24h with anterior to the left and dorsal towards the top. Scale bar: 30 μm.